Prior art message systems generally function upon the detection of coded signals which are predesignated to correspond to an address of an individual receiver. Some prior art digital coding systems operate by having a plurality of receivers asynchronously come on a timed basis to look for the presence of a digital word to determine if they should remain on for the detection of a possible message. This constitutes a form of battery saving to the receiver population.
A limitation of such prior art systems is that there is not a convenient method of arranging group calls at the transmitter site or paging terminal so that an arbitrary plurality of pagers may be activated simultaneously. A further limitation with the prior art occurs for tone and voice systems in which the paging receiver provides an alert time after which a voice message may be detected. Each time an individual paging receiver is paged with a voice message the alert time interval during which the pager user is warned so that he may respond to the subsequent audio message is lost to the system since no other information can be transmitted during that interval. If for example, another tone and voice pager were addressed during the alert time for the first addressed tone and voice pager at the conclusion of the second addressed tone and voice pagers alert time its audio channel would be enabled to catch a substantial portion of the voice message for the first addressed tone and voice pager thereby possibly confusing the pager users with respect to the messages they receive.
One aspect of the present invention includes the positioning of an activation code signal within a broadcast message system such that all receivers which have been correctly addressed remain in a ready state until the detection of an activate code signal which then causes simultaneous activation of the operational routine. Although the specific invention is embodied within a digital paging system it is clear to those skilled in the art that it may have many other uses and formats. Morever the use of such an activation control signal enables the interleaving of messages within a message alert time especially for a tone and voice pager which has been addressed and ensures that the second addressed tone and voice pager will not activate until it receives an activation code signal subsequent to its address. Thus there is no chance that the second address tone and voice pager could come on during the time period in which the first pager was receiving its variable length voice message. Another advantage of such a system is that it further allows interleaving of various types of messages including tone only, data and tone and voice into one signalling system thereby substantially enhancing the flexibility of the transmitted message system.